How to store data from form builder in database - php

Question

I am trying to create a form builder that will enable users generate survey form/page.
After the form is generated the form attribute is stored on a table.
Question 1:
Where can I store the form attribute knowing fully well that the number of fields user might add in the form is unknown.
Question 2:
Where and how do I store data submitted through the generated form when some one for example completes the survey form.
Should I create new tables on fly for each of the form attributes? If yes what if over a million forma are created which translates to a million tables.
Is this where multi-tenancy comes into play.
Please provide your answer based on best practices.

Answer 1

I think I get what you're asking, but why not create one table with 100 columns, labelled 1-100. Set a limit on the amount of fields a user can create(Limit 100).
Then, POST the fields and add a sql query to store the values...?
COMMENT ANSWER
If the user is already signed in filling this form I would personally do the POST request on the same page.
<?php if (isset($_POST['field1'])){
$valueforField1 = $_POST['field1'];
$valueforField2 = $_POST['field2'];
$valueforField3 = $_POST['field3'];
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "INSERT INTO Survey (field1, field2, field3) // I guess you would `have to add 100 fields here to accommodate the fields in your DB Also, you can set a default value in MySQL that way if field 56-100 is not set it has a value like 0 or add the value in this php file`
VALUES ('$valueforField1', '$valueforField2', '$valueforField3')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close(); ?>
COMMENT ANSWER or if you want to wait for the user to log in you can store all the values in a SESSION variable.
<?php
session_start();
if (isset($_POST['field1'];)){
if (!(isset($_SESSION['email']))){
$_SESSION['field1'] = $_POST['field1'];
// You would have to do 100 of these
}
}
?>